1. Technical Field
The present disclosure relates to a light emitting device that includes a semiconductor light emitting element and a resin member provided with an internal wiring, and to a method of manufacturing the same.
2. Description of the Related Art
Light emitting devices using a semiconductor light emitting element such as a light emitting diode are widely used because of ease of miniaturization and high light emission efficiency. The light emitting elements used in light emitting devices can be roughly divided into two types, namely, a face up type in which a surface of a semiconductor light emitting element for disposing a pad electrode is on the opposite side from the mounting surface, and a face down type in which a surface of a light emitting element for disposing an electrode is a lower surface that faces a mounting substrate.
In the face up type, a semiconductor light emitting element is mounted on leads or the like, and the semiconductor light emitting element and the leads are connected via bonding wires or the like. Accordingly, in a plan view of a semiconductor light emitting element disposed on a mounting substrate—that is, seen from a perpendicular direction relative to the mounting surface of the mounting substrate—portions of the wires are needed to be outer side of the semiconductor light emitting element, which imposes a limitation in miniaturization of the light emitting element.
On the other hand, in the face down type (or flip chip type), a pad electrode disposed on a surface of a semiconductor light emitting element and a wiring disposed on a mounting substrate can be electrically connected via a connector such as a bump or a metal pillar, which are positioned within the outer peripheral line of the semiconductor light emitting element in a plan view seen from a direction perpendicular to the mounting surface of the mounting substrate. This configuration allows forming of a CSP (Chip Size Package or Chip Scale Package) in which the size of a light emitting device (particularly the size in a plan view seen from a direction perpendicular to the mounting surface of the mounting substrate) is reduced almost to the size of the chip of a semiconductor light emitting element.
In recent years, in order to achieve further miniaturization, or in order to further improve the light emission efficiency, a face down type light emitting device has been proposed, in which a growth substrate (a light-transmissive substrate) such as sapphire has been removed, or the thickness of the growth substrate has been reduced.
The growth substrate is a substrate for growing thereon an n-type semiconductor layer and a p-type semiconductor layer that are components of a semiconductor light emitting element. The growth substrate also exhibits the effect of improving the mechanical strength of the light emitting device by supporting a semiconductor light emitting element that is small in thickness and low in strength. Accordingly, in a light emitting device in which the growth substrate is removed or the thickness of the growth substrate is reduced after formation of a semiconductor light emitting element, for example as disclosed in JP 2011-249426 A, a resin layer is disposed on an electrode side (the side facing the mounting substrate) for supporting a bare chip (i.e., a semiconductor light emitting element), and internal wirings made of metal pillars or other wirings are formed so as to penetrate through the resin layer, and the electrode and an external terminal are electrically connected to each other. With such a resin layer that includes an internal wiring, sufficient mechanical strength can be reliably obtained.
In the case where such a light emitting device that has a resin layer disposed on the electrode side is mounted on a mounting substrate by using an electrically conductive adhesive member, for example using a solder and a reflowing method, melted solder may be squeezed out from between the electrode for external connection of the light emitting device and the wiring pattern of the mounting substrate. In particular, when the solder is excessively supplied, the solder squeezed out from between the electrode for external connection of the light emitting device and the wiring pattern of the mounting substrate may rise along a side surface of the resin layer. The solder that rises up the side surface of the resin layer may cause bonding defects between the light emitting device and the mounting substrate, or may contaminate the light extraction surface resulting in a reduction in the light extraction efficiency.